1. Field of the Invention
The invention relates to an audio apparatus and in particular to a muting circuit utilized therein.
2. Description of the Related Art
Conventional audio systems typically utilize a muting circuit to disable audio output when the signal is undesirable or unnecessary. Such audio systems typically include audio amplifiers that amplify the input to drive a load such as a speaker. When muting is activated, the amplified audio signal is attenuated with respect to the input signal.
It is desirable to have a muting circuit that not only functions effectively while an audio system is powered-on but also during the system's power on/off cycle, since, when a power source of an audio amplifier is turned on or off, a sudden rising or falling of voltage is induced to cause a loud pop noise. Although the pop occurs only momentarily, it can cause damage to sensitive audio speakers.
A need exists for a muting circuit removing or reducing the pop noise during an abrupt change of the audio output in an audio apparatus.